Sliding honeycomb preform shaping mold and method

Abstract

The present invention discloses a sliding honeycomb preform shaping die, comprising a base plate and a core rod; the base plate is provided with a plurality of mutually parallel chutes, a plurality of core rods are arranged and slidably arranged in the chutes, and the core rods are hexagonal rod-shaped structures; when producing the honeycomb preform, a base plate with a corresponding chute spacing is selected according to the structural size of the preform to be produced; the core rods are then inserted into the honeycomb grid of the preform, and the core rods are regularly arranged in the chutes, with the distance between the core rods being consistent with the target thickness of the side walls of the honeycomb grid of the preform after molding; finally, epoxy resin is injected into the gaps in the core rods to complete the composite molding of the honeycomb preform, and demolding is performed. The present invention significantly improves the quality of honeycomb molding without increasing the cost; the sliding design changes the existing insertion and demolding methods, making the core rod insertion method possible, thereby greatly improving the insertion and demolding efficiency, and also reducing damage to the honeycomb.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material preparation and molding, and in particular relates to a sliding honeycomb preform molding die and a method. Background Art

[0002] In its initial state, the honeycomb preform is generally a flat flexible structure. To form a three-dimensional honeycomb composite material, a specific device is required to geometrically shape it (the honeycomb grid shape is generally a regular hexagon, and there are also shapes such as rectangles) before the final composite molding. At the same time, the honeycomb grid is generally a thin-walled structure, and the relative position relationship between the shaping devices such as the core rod determines the quality of the honeycomb wall composite molding.

[0003] Patent CN111674058A, "A Device and Method for Preparing a Carbon Fiber Three-Dimensional Braided Composite Material," proposes a composite molding method for honeycomb composites using a fixed mold. Fixed molds present the following challenges in practical use: First, the uncertainty in the order in which the mandrel is inserted and the geometric shape of the honeycomb preform significantly impact the quality of the honeycomb composite molding. The mandrel often is inserted too tightly or too loosely, resulting in uneven resin distribution in the honeycomb wall and even incomplete insertion of the mandrel, rendering the mold unusable. Second, during demolding, the limited constraint between the mandrel and the base plate can cause shear or torsional damage to the composite wall.

[0004] Patent CN113561522A "Device and method for preparing three-dimensional woven fiber-reinforced honeycomb based on thermal expansion flexible core mold" proposes the idea of ​​using a thermal expansion flexible core mold (such as silicone rubber) to improve molding quality and reduce demolding damage. To a certain extent, it solves the two types of problems mentioned above, but the high cost and the need to redesign the core mold for different honeycomb sizes and process temperatures hinder its application. Summary of the Invention

[0005] The present invention aims to provide a honeycomb preform shaping die with a relatively slidable core rod, so as to solve the problems of difficult mold insertion, difficult mold release and severe damage in existing fixed molds.

[0006] In order to achieve the purpose of the present invention, the present invention provides a sliding honeycomb preform shaping mold, which is characterized in that it includes a base plate and a core rod; a plurality of mutually parallel slide grooves are opened on the base plate, and a plurality of core rods are arranged and slidably set in the slide grooves, and the core rods are a hexagonal rod structure; when producing the honeycomb preform, a base plate with a corresponding slide groove spacing is selected according to the structural size of the preform to be produced; then the core rods are inserted into the honeycomb grid of the preform, and the core rods are regularly arranged in the slide grooves, and the distance between the core rods is consistent with the target thickness of the side wall of the honeycomb grid of the preform after molding; finally, epoxy resin is injected into the gaps of the core rods to complete the composite molding of the honeycomb preform, and demolding is performed.

[0007] Furthermore, the core rod consists of three parts: upper, middle and lower parts, among which the upper part is a hexagonal rod, the middle part is a polished rod for sliding in the slide groove, and the lower part is a bolt with threads; the hexagonal rod is used to fix and form the preform honeycomb grid, and the inclination design can ensure that the core rod does not damage the honeycomb preform during the process of penetrating the preform honeycomb grid; the polished rod and the slide groove form a clearance fit; the tightness of the bottom bolt determines the fixed or sliding state of the core rod in the slide groove.

[0008] Furthermore, the assembly process of the core rod is to insert the hexagonal rod into the honeycomb grid and then place it on the base plate. The diameter of the polished rod is equivalent to that of the slide groove. It is then fixed by the bottom bolt of the core rod. The position of the core rod can be adjusted by loosening the bottom bolt.

[0009] Furthermore, the side wall of the hexagonal rod has an inclination angle of 1° to 3°, so that the size of the hexagonal rod away from the polished rod end is smaller than the size of the hexagonal rod close to the polished rod end.

[0010] Furthermore, a scale is provided on the substrate, and the scale is used to judge the position of the core rod.

[0011] In order to achieve the purpose of the present invention, the present invention also provides a sliding honeycomb preform shaping method, comprising the following steps:

[0012] Step 1: Place the pre-treated substrate on a suspended stand and fix it;

[0013] Step 2: inserting the pretreated core rod into the first row of honeycomb cells of the honeycomb preform;

[0014] Step 3: Insert the mandrels that have been inserted into the honeycomb grid into the slide grooves on the base plate from one side of the base plate. After checking the honeycomb shape and the parallelism of the mandrels, fix the mandrels in the first row according to the honeycomb geometry, which will serve as the position reference for subsequent mandrels.

[0015] Step 4: insert the mandrel into the last row of honeycomb cells of the honeycomb preform, and insert the inserted mandrel into the base plate and fix it so that the honeycomb preform can maintain the honeycomb three-dimensional shape;

[0016] Step 5: Insert the mandrels corresponding to the remaining middle rows of honeycomb cells from the first row of honeycomb cells to the last row of honeycomb cells. Adjust the tightness of the mandrels in the middle and last rows of honeycomb cells according to the shape of the target honeycomb cells and fix them to complete the insertion of all mandrels.

[0017] Step 6: inject epoxy resin into the mold to complete the composite molding of the honeycomb preform;

[0018] Step 7: demoulding the formed honeycomb preform.

[0019] Furthermore, the pretreatment in step 1 and step 2 includes surface cleaning and applying a release agent.

[0020] Furthermore, in step 6, the specific process of composite molding of the honeycomb preform is as follows: first, the substrate is turned over, and the filling material is stuffed into the gap of the bottom slide to save resin; then, a guide net is arranged on the six sides of the mold, and the mold is placed in a vacuum bag; finally, epoxy resin is injected into the mold through the guide tube on the vacuum bag to complete the composite molding process.

[0021] Furthermore, in step 7, the process of demoulding the honeycomb preform after molding is to loosen the bottom bolts and use a wooden hammer to knock the core rod to demould. Due to the constraints of adjacent core rods, the damage during the demoulding process will be greatly reduced, and the demoulding process of the core rods is completed in sequence.

[0022] Compared with the existing technology, the significant progress of the present invention is: 1) by adopting the method of drilling through the slide groove on the base plate, the displacement coordination between the molded honeycombs can be easily achieved, significantly improving the honeycomb molding quality with almost no increase in cost; 2) the sliding design changes the existing mold insertion and demolding methods, making the core rod straight insertion method possible, thereby greatly improving the mold insertion and demolding efficiency, and also reducing damage to the honeycomb.

[0023] In order to more clearly illustrate the functional characteristics and structural parameters of the present invention, further description is given below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 It is a schematic diagram of the mold of the present invention;

[0026] Figure 2 It is a structural schematic diagram of the substrate in the present invention;

[0027] Figure 3 is a schematic diagram of the core rod structure of the present invention;

[0028] The reference numerals in the figure are: base plate 1, core rod 2, slide groove 3, scale 4, hexagonal rod 5, polished rod 6, bolt 7. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] like Figure 1-Figure 3 As shown, a sliding honeycomb preform shaping mold includes a base plate 1 and a core rod 2; the base plate 1 has a plurality of regularly arranged penetrating grooves 3, the core rod 2 can slide freely in the grooves, and the bottom of the core rod 2 has a bolt 7 for fixing, which is adjusted according to the tightness of the honeycomb grid.

[0031] Specifically, the core rod 2 consists of three parts: the upper part, the middle part, and the lower part, including: a hexagonal rod 5 with a slight inclination at the top, a smooth rod 6 for sliding in the middle part, and a bolt 7 with threads at the bottom. The hexagonal rod 5 is used to fix and form the hexagonal honeycomb grid, and its size is slightly smaller than the diameter of the honeycomb grid. The slight inclination design can ensure that the core rod 2 does not damage the honeycomb preform during the insertion process, and ensure the flow of resin; the smooth rod 6 forms a clearance fit with the slide groove 3; the tightness of the bottom bolt 7 determines whether the core rod 2 is in a fixed or sliding state.

[0032] Specifically, the substrate 1 is provided with a slide groove 3 and a scale 4 penetrating in the thickness direction. The size of the slide groove 3 is equivalent to the diameter of the middle polished rod 6 in the core rod 2, which not only ensures the stability of the core rod 2, but also ensures the smooth flow of the resin during the molding process; the scale 4 can be used to predict and judge the position of the core rod 2, including parallelism.

[0033] Specifically, the core rod 2 without a nut is inserted into the honeycomb column and then placed on the base plate 1 . The core rod 2 is fixed by the bolts 7 at the bottom. The position of the core rod 2 can be adjusted by loosening the bottom bolts 7 .

[0034] Example

[0035] In this embodiment, a honeycomb preform with a side length of 12 mm is shaped, and the honeycombs have 7 rows and 9 columns in total.

[0036] The size of the base plate 1 used is 240mm*120mm*12mm, and the material used is 30CrMn steel. Seven slide grooves 3 with a size of 200mm*6.5mm*12mm are opened on the base plate 1.

[0037] The dimensions of the core rod 2 used are: the upper hexagonal rod 5 has a side length of 11.5 mm, a height of 25 mm, a slope of about 3°, a large top and a small bottom, the middle polished rod 6 has a diameter of 6 mm and a length of 12 mm, and the bottom bolt 7 adopts the international coarse thread standard M6.

[0038] Put the mandrel 2 through the 7 honeycomb cells in the first column of the honeycomb preform, insert the mandrel 2 from the left side of the base plate 1, and place the middle three rows at 5.2mm according to the scale 4 of the base plate 1, and the remaining four rows at 10.4mm. Ensure that the center line of the bolt 7 is aligned with the scale, tighten the bolt 7 to completely fix the mandrel 2 and the base plate 1, and complete the benchmark setting of the honeycomb structure on the left side.

[0039] Then, insert the core rod 2 into the 7 honeycomb rods in the 9th column in sequence near the right side of the base plate, tighten the bolt 7, and keep the honeycomb preform in a three-dimensional shape.

[0040] On the substrate 1, position the core rod 2 of the second row of honeycombs approximately 10.4mm to the right relative to the first row. Adjust the position of the core rod 2 based on the tension and shape of the honeycomb. After adjustment, tighten the bolt 7 to secure the position of the core rod 2. Insert the core rod from the inside out. Repeat the above steps until the basic shape of all nine rows of honeycombs is completed. Finally, make overall adjustments based on the observed honeycomb shape.

[0041] The vacuum infusion process is used to perform the final composite molding of the honeycomb.

[0042] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0043] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A sliding honeycomb preform shaping mold, characterized in that: The invention comprises a base plate (1) and a core rod (2); the base plate (1) is provided with a plurality of mutually parallel slide grooves (3), a plurality of core rods (2) are arranged and slidably arranged in the slide grooves (3), and the core rods (2) are hexagonal rod-shaped structures; when producing a honeycomb preform, a base plate (1) having a corresponding distance between the slide grooves (3) is selected according to the structural size of the preform to be produced; then, the core rods (2) are inserted into the honeycomb grid of the preform, and the core rods (2) are regularly arranged in the slide grooves (3), and the distance between the core rods (2) is consistent with the target thickness of the side wall of the honeycomb grid of the preform after forming; Finally, epoxy resin is injected into the gap of the core rod (2) to complete the composite molding of the honeycomb preform, and demoulding is performed; The core rod (2) is composed of three parts: an upper part, a middle part, and a lower part, wherein the upper part is a hexagonal rod (5), the middle part is a polished rod (6) for sliding in the chute (3), and the lower part is a bolt (7) with a thread; the hexagonal rod (5) is used for fixing and forming the preform honeycomb grid, and the slope design can ensure that the core rod (2) does not damage the honeycomb preform during the process of penetrating the preform honeycomb grid; the polished rod (6) forms a clearance fit with the chute (3); the tightness of the bottom bolt (7) determines whether the core rod (2) is fixed or sliding in the chute (3); A scale (4) is provided on the substrate (1), and the scale (4) is used to judge the position of the core rod (2).

2. The sliding honeycomb preform shaping mold according to claim 1, characterized in that: The assembly process of the core rod (2) is as follows: the hexagonal rod (5) is inserted into the honeycomb grid and then placed on the base plate (1). The diameter of the polished rod (6) is equivalent to that of the slide groove (3). The core rod (2) is then fixed by the bottom bolt (7). The position of the core rod (2) can be adjusted by loosening the bottom bolt (7).

3. The sliding honeycomb preform shaping mold according to claim 1, characterized in that: The side wall of the hexagonal rod (5) has an inclination angle of 1° to 3°, so that the size of the hexagonal rod (5) at one end away from the polished rod (6) is smaller than the size at one end close to the polished rod (6).

4. A sliding honeycomb preform shaping method, the method being based on the sliding honeycomb preform shaping die according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: placing the pre-treated substrate (1) on a suspended stand and fixing it; Step 2: inserting the pretreated core rod (2) into the first row of honeycomb cells of the honeycomb preform; Step 3: insert the core rods (2) that have been inserted into the honeycomb grid into the slide groove (3) on the base plate (1) from one side of the base plate (1), check the honeycomb shape and the parallelism of the core rods (2), and then fix the first row of core rods (2) according to the honeycomb geometric relationship as the position reference for subsequent core rods; Step 4: inserting the core rod (2) into the last row of honeycomb cells of the honeycomb preform, and inserting the inserted core rod (2) into the base plate (1) and fixing it, so that the honeycomb preform can maintain the honeycomb three-dimensional shape; Step 5: Insert the core rods (2) corresponding to the remaining middle columns of honeycomb cells in the direction from the first column of honeycomb cells to the last column of honeycomb cells. Adjust the tightness of the core rods (2) of the middle and last columns of honeycomb cells according to the shape of the target honeycomb cells and fix them to complete the insertion of all core rods. Step 6: inject epoxy resin into the mold to complete the composite molding of the honeycomb preform; Step 7: demoulding the formed honeycomb preform.

5. The sliding honeycomb preform shaping method according to claim 4, characterized in that: The pretreatment in step 1 and step 2 includes surface cleaning and applying a release agent.

6. The sliding honeycomb preform shaping method according to claim 4, characterized in that: In step 6, the specific process of composite molding of the honeycomb preform is as follows: first, the substrate (1) is turned over, and the gap of the bottom slide (3) is stuffed with filling material to save resin; then, a guide net is arranged on the six sides of the mold, and the mold is placed in a vacuum bag; finally, epoxy resin is injected into the mold through the guide tube on the vacuum bag to complete the composite molding process.

7. The sliding honeycomb preform shaping method according to claim 4, characterized in that: In step 7, the process of demoulding the honeycomb preform after molding is as follows: loosening the bottom bolt (7) and using a wooden hammer to knock the core rod (2) for demoulding. Due to the constraints of the adjacent core rods (2), the damage during the demoulding process will be greatly reduced, and the demoulding process of the core rods (2) is completed in sequence.

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